How to generate the hash of public key in Bitcoin

[PrettyGirl741963]

I'm trying to hash the public key with SHA256 and then ripemed160 and get the hash. but it gives the error "System.ArgumentOutOfRangeException: 'Index and length must refer to a location within the string. Parameter name: length'" I think it's because of the odd number of characters of the public key.

Public key: 2b4632d08485ff1df2db55b9dafd23347d1c47a457072a1e87be26896549a8737

Hash should be: 93ce48570b55c42c2af816aeaba06cfee1224fae

Code:

Imports System.Security.Cryptography
Imports System.Text
Imports System.Globalization
Imports System.Numerics

Private Function HexStringToByteArray(ByVal shex As String) As Byte()
    Dim B As Byte() = Enumerable.Range(0, shex.Length).Where(Function(x) x Mod 2 = 0).[Select](Function(x) Convert.ToByte(shex.Substring(x, 2), 16)).ToArray()
    Return Enumerable.Range(0, shex.Length).Where(Function(x) x Mod 2 = 0).[Select](Function(x) Convert.ToByte(shex.Substring(x, 2), 16)).ToArray()
End Function


Private Sub Button12_Click(sender As Object, e As EventArgs) Handles Button12.Click

Dim public_key as String = "2b4632d08485ff1df2db55b9dafd23347d1c47a457072a1e87be26896549a8737"
   Dim pubkey_hash As String

    Dim sha256 As SHA256 = SHA256Managed.Create()
      Dim bytes As Byte() = HexStringToByteArray(public_key)
    Dim hash As Byte() = sha256.ComputeHash(bytes)
    Dim stringBuilder1 As New StringBuilder()

    For i As Integer = 0 To hash.Length - 1
        stringBuilder1.Append(hash(i).ToString("X2"))
    Next

    bytes = HexStringToByteArray(stringBuilder1.ToString())

    Dim ripemd160 As RIPEMD160 = RIPEMD160Managed.Create()
    Dim hash_160 As Byte() = ripemd160.ComputeHash(bytes)

    Dim stringBuilder2 As New StringBuilder()

    For i As Integer = 0 To hash_160.Length - 1
        stringBuilder2.Append(hash_160(i).ToString("X2"))
    Next

    Dim arr() As Char = stringBuilder2.ToString 

    pubkey_hash = arr.tostring
    TextBox14.Text = pubkey_hash


   End Sub

what I want to achieve is : bitcoin Public key --> SHA256 --> RIPEMD160 = final hash

[pooya87]

Code:

Dim public_key as String = "2b4632d08485ff1df2db55b9dafd23347d1c47a457072a1e87be26896549a8737"
Dim bytes As Byte() = System.Text.Encoding.Unicode.GetBytes(public_key)

your "public_key" variable is a hexadecimal string not a Unicode string and that means your initial byte array that you hash is the wrong value.
you already have a function called "HexStringToByteArray", i'm not sure if it is a correct conversion but if it is then use that instead of "System.Text.Encoding.Unicode.GetBytes"

[PrettyGirl741963]

Public keys are not hexadecimal, this is an actual bitcoin public address :

mwZVuA4D5TSSymdXZza4S1YhZFnH2fcaeG

  see it's not a hexadecimal

[pooya87]

Public keys are not hexadecimal, this is an actual bitcoin public address :

mwZVuA4D5TSSymdXZza4S1YhZFnH2fcaeG

  see it's not a hexadecimal

there is a difference between "public key" and an "address" or if you like public address. public key is an x,y coordinate of a point located on the elliptic curve while address is a base58 encoding of hash of the public key.
what you posted here is a testnet address and it is using base58 encoding. (you still should use Unicode to decode this)

however public keys are usually presented in base-16 or hexadecimal format. additionally in your code the variable called public_key is indeed a public key and is indeed using hexadecimal encoding.

[PrettyGirl741963]

Public keys are not hexadecimal, this is an actual bitcoin public address :

mwZVuA4D5TSSymdXZza4S1YhZFnH2fcaeG

 see it's not a hexadecimal

there is a difference between "public key" and an "address" or if you like public address. public key is an x,y coordinate of a point located on the elliptic curve while address is a base58 encoding of hash of the public key.
what you posted here is a testnet address and it is using base58 encoding. (you still should use Unicode to decode this)

however public keys are usually presented in base-16 or hexadecimal format. additionally in your code the variable called public_key is indeed a public key and is indeed using hexadecimal encoding.

Thank you for the explanation I didn't know that, but I changed the code to convert it to byte array from hex string. then it gives me this error. I think it's because of the odd number of characters of the public key

System.ArgumentOutOfRangeException: 'Index and length must refer to a location within the string.
Parameter name: length'

[PrettyGirl741963]

updated with code, now gets an error